Various examples exist in the field for determining a tire pressure status. For instance, U.S. Pat. No. 6,441,732 issued to Laitsaari et al. discloses a system for displaying tire characteristics. A vehicle depot such as for example a gas station, a bus stop or a truck terminal, is equipped with a communications system to receive data from a vehicle that represents the operational characteristics of the tires of the vehicle. The information may be automatically transmitted to an appropriate transceiver located at the gas station when the vehicle enters a preset perimeter of, or is a given distance from, the gas station. Thus, when the operator of the vehicle begins to pump gas or input air to the tires of his vehicle, he could readily view the operational characteristics, or the status, of the tires of his vehicle at a display that is mounted either at the gas pump, the handle of the gas hose, the housing of the air supply or some other convenient location at the gas station. In addition, the attendant at the gas station can view the operational characteristics of the tires of any of the vehicles parked at the gas station so that, if tire abnormalities are observed, the attendant could inform the operator of the vehicle that has the abnormal tire(s) that there is a potential problem. A permanent record of the operational characteristics of the tires of any of the vehicles may be printed out. Displays may also be incorporated to roadside signs/billboards so that passing motorists may readily ascertain from the displays the operational characteristics of the tires of their vehicles. Simple alert messages that apprize the motorists, either at the vehicle depot or passing the roadside sign/billboard displays, of whether attention needs to be directed to the tires of their vehicles may be displayed in place of the actual tire operational characteristics.
U.S. Pat. No. 6,612,165 issued to Juzswik et al. discloses a tire pressure monitoring system with pressure gauge operating mode for indicating when air pressure within a tire is within a predetermined pressure range. A tire inflation pressure monitoring system and a method for monitoring air pressure within a tire are provided. The system includes a tire based unit for sensing air pressure within the tire and for transmitting a pressure signal indicative thereof. The system also includes a vehicle based unit for receiving the pressure signal and for comparing the pressure signal to a predefined pressure range. The vehicle based unit is operable in one of (i) a normal operating mode that outputs an alert signal in response to the air pressure within the tire being outside of the predefined pressure range and (ii) a pressure gauge operating mode that outputs an in-range signal in response to the air pressure within the tire being within the predetermined pressure range.